The present invention generally relates to a flare-type pipe joint, and particularly relates to a flare-type pipe joint which is suitable for use for air/oil piping in a vehicle.
In a vehicle, piping of brake tubes, fuel pipes, and the like, is performed. In order to facilitate assembling work or arrangement of piping, a flare-type pipe joint constituted by a pair of pipes, one having a tranpet-shaped flare portion and the other having a conical flange surface, is used as the pipe joint.
This flare-type pipe joint is configured such that the flare portion abuts on the conical flange surface so as to seal pipes with each other. The technique for improving the reliability of the sealing property of the abutment portions is disclosed in Japanese Utility Model Unexamined Publication Nos. Hei-6-63983 and Hei-2-122288, and Japanese Patent Unexamined Publication No. Hei-6-34084, etc.
The above Japanese Utility Model Unexamined Publication No. Hei-6-63983 discloses a technique in which an enlarged diameter portion is formed on a part of a conical flange surface to thereby give a mechanical elastic means to the flange surface. The above Japanese Utility Model Unexamined Publication No. Hei-2-122288 discloses a packing which is buried into a pipe inner hole of a conical flange. The above Japanese Patent Unexamined Publication No. Hei-6-34084 discloses a technique in which a groove is provided in a conical flange surface and an O-ring is fitted in the groove.
If an elastic portion is provided on a conical flange surface and the flange surface is made to abut on a flare portion as described in the above technique, the reliability of sealing is improved. In the above Japanese Utility Model Unexamined Publication No. Hei-2-122288 and Japanese Patent Unexamined Publication No. Hei-6-34084, however, there has been such a disadvantage that the number of parts increases because of requirement of a sealing material such as a packing or an O-ring.
In the above Japanese Utility Model Unexamined Publication No. Hei-6-63983, since the conical flange surface abuts directly on the flare portion, it is necessary to make the surface processing high in accuracy with respect to both the surfaces. Further, in the above Japanese Patent Unexamined Publication No. Hei-6-34084, since a groove for an O-ring is provided, it is necessary to further provide a cutting step.